This invention relates to a folded air bag cushion for use in a supplemental inflatable restrain system of a vehicle and more particularly to an air bag and method of folding such air bag which permits efficient storage of the air bag and controlled bias deployment of the air bag in a lateral direction upon encountering an outward obstruction.
It is well known to utilize inflatable air bag cushions within a transportation vehicle to absorb a portion of the kinetic energy of an occupant during a collision event. Air bag cushions for the protection of a vehicle passenger may be inflated from a storage position substantially opposing the passenger such as from the instrument panel or the like. The air bag cushion is typically stored in a folded condition in fluid communication with a gas emitting inflator within a storage structure commonly referred to as a module. Due to the substantial inflated volume of the air bag cushion, such cushions are typically subjected to multiple folding operations in order to conform the folded air bag structure to the space requirements of the associated module. One such folding procedure is described in U.S. Pat. No. 5,425,551 the contents of which are incorporated by reference as if fully set forth herein.
In general, it is believed that compacting the air bag cushion into a smaller area may be desirable for space allocation purposes. However, the desire for a smaller storage area may not override the need for the air bag cushion to exhibit rapid and controlled deployment upon introduction of the inflation gas. Thus, the general space saving benefits realized by having the footprint of the air bag cushion and related module occupy a relatively small area should not prevent the air bag cushion from expanding quickly and efficiently into its desired operative position in substantially opposing relation to the occupant to be protected as the inflation gas is introduced. Moreover, the folding operation utilized to achieve compaction of the air bag cushion should not be overly complex and should be adaptable to a wide variety of air bag cushion constructions of different sizes and shapes.
The need for a highly versatile folding technique is particularly acute in the packaging of air bag cushions for use in opposing relation to a non-operating passenger such as a side or rear seated passenger within a vehicle. While the operator of the vehicle is generally positioned within a relatively well defined space in front of the operating controls, non-operating passengers may be positioned over a much more expansive region. In order to cover such expansive regions, air bag cushions for the protection of passengers may be of substantial volume and take on much more complex shapes than air bag cushions used for the protection of a vehicle operator.
Due to the fact that some passengers such as persons of small stature may be seated in relatively close proximity to the air bag module, it has also been proposed to direct the inflating air bag cushion in a generally lateral direction relative to the opposing passenger during the early stages of inflation in those instances where the passenger is seated within a predefined short distance away from the module opening. Such lateral deployment may provide a more gentle cushioning interaction between the air bag cushion and the passenger which may be desirable for persons of small stature. One such configuration which utilizes a flap element to selectively close off the top deployment opening to bias and divert the deploying air bag cushion in a lateral direction until the top flap is unfolded is set forth in U.S. Pat. No. 5,348,343 the contents of which are incorporated into this specification by reference as is fully set forth herein.
While the selection of air bag cushion geometry and/or the use of deployment biasing systems are believed to be useful in the achievement of potentially desirable deployment characteristics, the folding techniques used to package the air bag cushion are nonetheless important in the realization of these benefits.
This invention provides advantages and alternatives over the prior art by providing a packaged air bag cushion and technique for folding the air bag cushion into a compact arrangement in a highly efficient manner which promotes controlled rapid straight forward deployment of the air bag cushion if no obstruction is encountered while at the same time biasing the expansion in a generally lateral direction around the side of the occupant if an obstruction is encountered during the early stages of inflated deployment. An easily executed series of folding steps is utilized to achieve a desired predefined folded surface geometry for storage within the available storage facility within the vehicle and to promote the desired deployment characteristics. The folded structure has a concentration of folds along one lateral side to aid in deployment in a lateral direction.
These advantages are accomplished in a potentially preferred form of the invention by providing an air bag cushion folded for storage within a vehicle to achieve a predefined folded surface geometry footprint of a predefined width and height corresponding to a desired storage location for the folded air bag cushion. A portion of the air bag cushion extending along a first lateral boundary edge for deployment inboard or outboard of the passenger seating location is folded in a multi-layer construction inwardly towards a first internal lateral boundary line to establish a first lateral edge of the predefined folded surface geometry footprint. A portion of the air bag cushion disposed along the opposing lateral boundary edge is folded inwardly across the top side of the air bag cushion in a substantially hinging flap-like fashion along a second internal lateral boundary line corresponding to a second lateral edge of the predefined folded surface geometry. The portion of the air bag folded in flap-like fashion establishes a covering flap extending across the top side of the air bag cushion substantially between the first and second internal lateral boundary lines. The application of such lateral folds yields an intermediate folded construction of elongate configuration having a width substantially corresponding to the desired width of the predefined folded surface geometry footprint. The top and bottom ends of the intermediate folded construction are folded or rolled inwardly in a manner such as disclosed in U.S. Pat. No. 5,425,551 until reaching the respective upper and lower boundary lines of the predefined folded surface geometry footprint. The resultant folded air bag configuration having the predefined folded surface geometry footprint may thereafter be packed into an appropriate containment housing in fluid communication with a gas emitting inflator. It is contemplated that such a packaged air bag cushion may be used either alone or in combination with a biasing guide member such as disclosed in U. S. Pat. No. 5,348,343 to promote lateral movement by the air bag cushion in instances where an opposing obstruction is encountered.
In accordance with other potentially preferred aspects of the invention, the air bag cushion is formed of a highly pliable material such as a woven textile fabric either with or without a permeability blocking coating. Such a woven textile fabric is preferably formed of multi-filament yarns having a relatively low denier per filament linear density rating of about 3 to about 8 denier per filament. Low denier per filament ratings may promote the compact packaging of the air bag cushion using the folding techniques according to the present invention.
Advantageously, the packaging techniques and resulting air bag assembly according to the present invention promote potentially desireable inflation characteristics and are highly adaptable to air bag cushions having a wide variety of geometries. Moreover, the individual folding steps avoid undue complexity which may reduce the opportunity for error. The present invention is thus believed to provide new and useful advantages over the state of the art.